The present invention relates, in general, to impact switches, and more particularly to an impact switch which is sensitive only to horizontally directed forces of a predetermined magnitude and which is insensitive to vertical motion.
Impact switches of various designs and sensitive to predetermined forces are well known in the art and find use, for example, in safety devices for vehicles. Such switches may be used to actuate safety equipment such as passenger restraint inflatable air bags, or to disconnect the vehicle electrical system when the vehicle is involved in an accident. A variety of such impact-sensitive switches have been developed in the prior art, as exemplified by U.S. Pat. No. 3,720,426 to Johnston, U.S. Pat. No. 3,784,773 to Jubenville, and others.
One of the problems encountered with prior safety switches of the impact type is that many are overly sensitive to the normal jolts and bounces to which a vehicle may be subject, and thus may respond in a non-impact situation to activate the safety equipment. Such unintended actuation can be extremely dangerous, and accordingly it is important to provide an impact switch that will be activated only upon the occurrence of specific conditions. Since such switches profoundly affect the safety of a vehicle's occupants, it is extremely important that impact switches of this type be extremely reliable and that they have a very small response time so that when an emergency situation arises, the safety equipment is instantly activated. Further, since such switches are in wide use, it is equally important that they be easy to make and to install, and thus that they be of a simple, uncomplicated construction.